Chemical stability of solutions of niobium V in molten NaCl-KCl at 750 C

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Journal of the Electrochemical Society; (United States)

DOI:https://doi.org/10.1149/1.2043859· OSTI ID:6538864

Arurault, L; Poignet, J C ^[1]; Bouteillon, J ^[2]

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1. Centre de Recherche en Electrochimie Minerale et en Genie des Procedes, Saint Martin d'Heres (France)
2. Centre de Recherche en Electrochimie Minerale et en Genie des Procedes, Saint Martin d'Heres (France) Univ. Joseph Fourier, Grenoble (France)

Recently, niobium metal has raised much interest because of its good properties in nuclear technology, electronics, metallurgy, and possibly superconductors. The necessity, for most of these uses, to have highly pure niobium explains why research started in the early sixties for obtaining this metal by molten salt electrolysis as an alternative process to thermal reduction. Solutions of Nb(V), mainly as K[sub 2]NbF[sub 7], in molten NaCl-KCl at 750 C, were studied by potentiometry, linear sweep voltammetry, chemical and X-ray analysis. Voltammograms at tungsten electrodes showed that the use of silica parts in contact with the melt had to be strictly discarded. The variations of the open-circuit potentials of tungsten or vitreous carbon electrodes, recorded during several weeks, showed that the Nb(V) species was not stable and underwent slow reduction to Nb(IV). This hypothesis was reinforced by chemical and X-ray analysis of the frozen melts. Reduction of Nb(V) to Nb(IV) was fast and complete when niobium metal was introduced in the melt.

• OSTI ID: 6538864
• Journal Information: Journal of the Electrochemical Society; (United States), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 142:1; ISSN JESOAN; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400* -- Electrochemistry
ALKALI METAL COMPOUNDS
CHEMICAL REACTIONS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
ELECTROCHEMISTRY
ELECTROLYSIS
ELEMENTS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
LYSIS
MEASURING METHODS
METALS
MOLTEN SALTS
NIOBIUM
NIOBIUM COMPOUNDS
NIOBIUM FLUORIDES
POTASSIUM CHLORIDES
POTASSIUM COMPOUNDS
REDUCTION
REFRACTORY METAL COMPOUNDS
SALTS
SODIUM CHLORIDES
SODIUM COMPOUNDS
SYNTHESIS
TEST FACILITIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS